PAT 25A generation?

May 01, 2009 3 Replies

I don't have a PA tester but wonder how the 25A for the class 1 appliance earth test is generated. Does it has to be on for suffient time to blow the single remaining strand of copper or just long enough for a single voltage sample to be taken? What is the source?


On Fri, 01 May 2009 15:01:04 GMT, Geo had this to say:

The tester contains a transformer which provides a low voltage high current supply.

I did one for an automated product tester. Ended up with (ISTR) testing with 40Amps for about 4 seconds, with voltage being measured continuously. Yes, those remaining copper strands do happen surprisingly often and burn out within the first second, (cue process improvements!). Power came from a normal 100W mains transformer. It's

12V secondary winding cut off and a couple of turns of 10mm^2 wound on in it's place.

Why 25A when the standard kit for fixed wiring uses 200mA?

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